Intro to CSS

CSS. What is It?

Cascading Style Sheets

Add styles to HTML pages by targeting specific tags

CSS Rule breakdown

property

selector

CSS Rule Breakdown

CSS Rule Breakdown

You can also have several declarations in a single rule

How to add styles

  • External style sheet - Best way to go. Separate document with .css suffix. Document is then linked to you HTML page.
  • Embedded style sheet- Styles are placed in the <head> tag and only effect the tags in that HTML document
  • Inline styles - Styles are placed in an HTML tag using the "style" attribute. Only effects the tag that the style was placed in.

DEMO

  • add styles via embedded, linked or inline 

The cascade

  • If there's conflicting styles, the browser uses the "cascade" to determine which style to show.

  • You can override all styles by assigning the !important indicator to a declaration.

the cascade

The more specific the tag is, the greater chance of the browser choosing to load that style

ex: em{color:green;}
p em {color: red;}

 

The browser will load the p em style because it's more specific

Demo

the cascade

The items at the top will override items below it

the cascade

If rules of identical weight conflict, which ever comes last, wins

p {color:green;}
p {color:yellow;}

p{ color:green;
color:yellow; }

grouping selectors

You can apply a style to more than one selector

 

p, em, li {color:red;}

Demo

the box model

  • Every element on the page is it's own "box"

  • You can apply properties such as margins, padding, backgrounds and borders

  • You can also reposition them

formatting text

properties

font-family: Arial, Helvetica, sans-serif;

font-size: size of font (ems, px or %)

font-weight: boldness (normal, bold, or value)

font-style: italics (normal, italic, oblique, inherit)

font-variant: small caps (normal, small-caps, inherit)

font: style weight variant size/line-height family

text-color: changes the font color (name or  hexdex #)

Using ems

EMs are a relative measurement and is based on the parents measurement. 

 

The default body size is always set to 1em (16px)

Using Ems

1em is about 16px;

 

You can convert from ems using a simple math equation
current px measurment/16px = em
12px/16px=.75em;

 

Always include the decimal for an exact conversion

Demo

Using Ems

Remember: ems are based on the inherited size of the element.

 

If I set an article tag to 18px (1.125em) and I wanted an H1 tag inside the article tag to be 14px, my equation would change to:
14px/18px=.77777778em

 

target/content=result

CHOOSING A FONT

DEMO: Using Google Fonts

More CSS Properties

  • line-height: leading (number, percentage, normal, inherit)
  • text-indent: indents the first line of a paragraph (#)
  • text-align: aligns text (left, right, center, justify, inherit)
  • text-decoration: applies a line to the text (none, underline, overline, line-through, blink)
  • text-transform: caps or lowercase text (none, capitalize, lowercase, uppercase, inherit)

More CSS Properties

  • letter-spacing: kerning (#)
  • text-shadow: applies a shadow to text (5px, 5px, #777) (horizontal offset, vertical offset, shadow color)
  • vertical align: vertical alignment of inline elements (baseline, sub, super, top, middle, bottom, #)
  • visibility: hides elements (visible, hidden collapse, inherit)

Demo

SELECTORS

selector types

  • element selectors: p {font-size:12px}
  • grouped selectors: p, em, li {font-size:12px}

selector types

  • Contextual Selectors: Selects an element based on its context

  • Descendant Selectors: targets an element contained within another element

    • p em {color:green;} Will only target em within a p

 

selector Types

  • Child Selector: targets only the direct children

    p >em{color:green} will only target an em tag if it's within the p with no other tags in between.

     

  • Adjacent Sibling: targets an element that comes directly after another element with the same parent
    p+em{color:green} will only target an em tag if it directly comes after a </p>

 

Contextual Selectors

selector Types

 

  • General Sibling: selects an element that shares a parent and occurs after in the source order. BUT it doesn't have to be directly after
  • p~em:{color:green;} will target an em tag if it comes after the p (there can be tags in between)
  • Does not work in IE8 or lower

 

Contextual Selectors

selector Types

target elements by their id values

<p id="red">Blah Blah</p>

#red{color:red;}

 

 

ID Selectors

selector Types

Works like an id selector except you can target a class

<li class="textChange">bla bla</li>

.textChange{}

 

 

Class Selectors

Demo

specificity within selectors

 

1. ID selectors

 

2. Class selectors

 

3. Contextual selectors

 

4. Individual element selectors

 

strong{color:red;}
h1 strong{color:green;}

 

The top will override what's below it

styling bullets

  • list-style-type: changes the marker. By default it's a disc (disc, circle,square,decimal, lower-alpha, upper-alpha, lower-roman, upper-roman, lower-greek)
  • list-style-position: changes where the bullet is placed. Default is outside of the content area (inside, outside, inherit)
  • list-style-image: allows you to add an image for a bullet (url:path to image)

 

Demo

CSS Colors

color values

  • Name - color:red  
  • RGB Value - color: rgb (200, 178, 230)
  • Hexdex #- color: #888f90
  • HSL (new in CSS3) - color: hsl (265, 32%, 90%)ways have a name

There are several ways you can specify a color

opacity values

  • color: rgba(12, 130, 20, 50%)
  • color:#ffffff; opacity: .5

You can specify an opacity value of a color two different ways:

Color Inspiration

Background Images

  • background-image: url(path to file);
  • background repeat: (repeat, repeat-x, repeat-y, no-repeat, inherit)
  • background-position: (measurement, percentage, left, center, right, top, bottom, inherit)
  • background-attachment: (scroll, fixed, local, inherit)

Background Images

shorthand: shorthand (can appear in any order)

background: background-color background-image background-repeat background-attachment background-position

 

background:url(kittens.jpg) no-repeat left top fixed #444444;

Demo

Background Images

You can also call multiple background images. The image called first will be placed in front.

 

background-image: url(kittens.jpg), url(dogs.jpg);
background-position: left top, center top;
background-repeat: no-repeat, repeat-y;

Background Images

You can also use the short hand version to call multiple background images:

 

background: url(kittens.jpg) left top no-repeat, url (dogs.jpg) left center, repeat-y;

pseudo class selectors

  • :link - applies a style to an unclicked link
  • :visited - applies a style to an already clicked link
  • :focus - applies a style when an element is ready for input
  • :hover - applies a style when a link is hovered over with mouse
  • :active - applies a style when the element is being clicked

are applied to already existing classes

Demo

pseudo element selectors

  • :first-line (color, font, background, word-spacing, letter-spacing, text-decoration, vertical-alignment, text-transform, line-height)
  • :first-letter (color, font, text-decoration, text-transform, vertical-align, padding, background, margin, line-height, border, float, letter-spacing, word-spacing)
  • p:first-letter{color:green;}
    p:first-line{font-size:18px}

are applied to already existing classes

pseudo element selectors

  • :before - inserts content before the specified element
  • :after- inserts content after the specified element

     

    p:before{
          content:"Once upon a time";
          font-weight:bold;
          color:purple;
    }

are applied to already existing classes

attribute selectors

 

  • element[attribute]: selects an element that has a the specified attribute
     

img[title]{border3px solid #555;}

 

element [attribute="exact value"]

CSS: input[type="text"]{border:1px solid #444;}
 

are applied to already existing classes

CSS Gradients, Rounded corners & Drop shadows

Gradients

CSS Gradient Tools

CSS gradients are very complex. Using a tool can help simplify the process

Rounded Corners

Use the property border-radius:

.square{ 
  border-radius: 25px;
  border: 2px solid #73AD21;
}

Below sets all 4 corners to a radius of 25px;

.square{ 
  border-top-left-radius: 15px;
  border-top-right-radius: 20px;
  border-bottom-right-radius: 25px;
  border-bottom-left-radius: 30px;
  border: 2px solid #73AD21;
}

You can also affect all 4 corners independently

Drop Shadows

Use the property box-shadow adds a drop shadow to an elements frame

box-shadow: offset-x offset-y blur color;

.square{ 
  border-radius: 25px;
  box-shadow: 5px 5px 2px #444;
}

You can also add additional values:

box-shadow: offset-x offset-y blur  spread color;

.square{ 
  border-radius: 25px;
  box-shadow: 2px 2px 2px 1px rgba(0, 0, 0, 0.2);
}

Drop Shadows

You can also use numerous web tools to help generate a box shadow

TEXT Shadows

You can also add drop shadows to text

text-shadow:  offset-x offset-y blur color

h1{
   text-shadow: 1px 1px 2px black; 
}

Text Shadow Tools

LWD Week 5A

By shadow4611

LWD Week 5A

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